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Stack

caution

This is the SST v1.x Constructs doc. SST v2 is now released. If you are using v2, see the v2 Constructs doc. If you are looking to upgrade to v2, check out the upgrade steps.

The Stack construct extends cdk.Stack. It automatically prefixes the stack names with the stage and app name to ensure that they can be deployed to multiple regions in the same AWS account. It also ensure that the stack uses the same AWS profile and region as the app. They're defined using functions that return resources that can be imported by other stacks.

Examples​

Creating a new stack​

import { StackContext } from "@serverless-stack/resources";

export function MyStack({ stack }: StackContext) {
  // Define your stack
}

Adding to an app​

Add it to your app in stacks/index.js.

import { StackA } from "./MyStack";
import { StackB } from "./MyStack";

export default function main(app) {
  app
    .stack(StackA)
    .stack(StackB);

  // Add more stacks
}

Here app is an instance of App.

Note that, setting the env for an individual stack is not allowed.

app.stack(MyStack, { env: { account: "1234", region: "us-east-1" } });

It will throw this error.

Error: Do not directly set the environment for a stack

This is by design. The stacks in SST are meant to be re-deployed for multiple stages (like Serverless Framework). And so they depend on the region and AWS profile that's passed in through the CLI. If a stack is hardcoded to be deployed to a specific account or region, it can break your deployment pipeline.

Configuring stack name​

By default, the name of the CloudFormation stack is the stage name, app name, and the stack function name joined by -, ie. stage-app-MyStack.

You can override the stack function name by passing in id. In this case, the CloudFormation stack name is stage-app-my-stack.

import { MyStack } from "./MyStack";

export default function main(app) {
  app.stack(MyStack, { id: "my-stack" });
}

Alternatively, you can override the CloudFormation stack name directly by passing in stackName.

import { MyStack } from "./MyStack";

export default function main(app) {
  app.stack(MyStack, { stackName: `${app.stage}-my-hello-stack` });
}

Note that, stackName need to be parameterized with the stage name. This ensure an app can be deployed to multiple stages with unique stack names.

Sharing resources between stacks​

Resources defined in a stack can be used by other stacks. This allows you to have granular stacks that contain only related resources.

Stack functions can return any resources they want to expose to other stacks.

import { StackContext } from "@serverless-stack/resources"

export function MyStack({ stack }: StackContext) {
  const table = new Table(stack, "table")
  return {
    table
  };
}

Other stacks can import these resources by utilizing the use function

import { StackContext, use } from "@serverless-stack/resources"
import { MyStack } from "./MyStack"

export function AnotherStack({ stack }: StackContext) {
  const { table } = use(MyStack);
  // Use table
}

Async stacks​

Asynchronous calls are supported in stack functions but be careful when using this as you can introduce external state that makes your deployments less deterministic

Simple add an async modifier to your function definition

import { StackContext } from "@serverless-stack/resources"

export async function MyStack({ stack }: StackContext) {
  const foo = await someAsyncCall();
  // Define stack
}

When initializing the stack, make sure you call await

import { MyStack } from "./MyStack"
export default function main(app: sst.App) {
  await app.stack(MyStack);
}

Accessing app properties​

The stage, region, and app name can be accessed through the app object. In your stacks (for example, stacks/MyStack.js) you can use.

function MyStack({ stack, app }: StackContext) {
  app.stage;
  app.region;
  app.name;
}

You can use this to conditionally add stacks or resources to your app.

Specifying default function props​

You can set some function props and have them apply to all the functions in a stack. This must be called before any functions have been added to the stack; so that all functions will be created with these defaults.

function MyStack({ stack }: StackContext) {
  stack.setDefaultFunctionProps({
    timeout: 20,
    memorySize: 512,
    runtime: "go1.x",
    environment: { TABLE_NAME: "NOTES_TABLE" },
  });
}

It'll also override any props set by the App's setDefaultFunctionProps, while merging the environment and permission props.

Updating default function props​

You can also use addDefaultFunctionPermissions, addDefaultFunctionEnv, and addDefaultFunctionLayers to progressively add more permissions, environment variables, and layers to the defaults. These can be called multiple times and from anywhere.

However, they only affect the functions that are created after the call.

function MyStack({ stack }: StackContext) {
  new Api(stack, "Api1", {
    routes: {
      "GET /": "src/hello.main",
    },
  });

  stack.addDefaultFunctionEnv({
    TABLE_NAME: "NOTES_TABLE",
  });

  stack.addDefaultFunctionPermissions(["s3"]);

  stack.addDefaultFunctionLayers([mylayer]);

  new Api(stack, "Api2", {
    routes: {
      "GET /": "src/world.main",
    },
  });
}

So in the above example, the addDefaultFunctionPermissions and addDefaultFunctionEnv calls will only impact the functions in Api2.

Prefixing resource names​

You can optionally prefix resource names to make sure they don't thrash when deployed to different stages in the same AWS account.

You can do so in your stacks.

scope.logicalPrefixedName("MyResource"); // Returns "dev-my-sst-app-MyResource"

This invokes the logicalPrefixedName method in App that your stack is added to. This'll return dev-my-sst-app-MyResource, where dev is the current stage and my-sst-app is the name of the app.

Adding stack outputs​

export function MyStack({ stack }: StackContext) {
  const topic = new Topic(stack, "Topic");
  const queue = new Queue(stack, "Queue");
  stack.addOutputs({
    TopicArn: topic.snsTopic.topicArn,
    QueueArn: topic.sqsQueue.queueArn,
  });
}

Adding stack exports​

export function MyStack({ stack }: StackContext) {
  const topic = new Topic(stack, "Topic");

  stack.addOutputs({
    TopicArn: {
      value: topic.snsTopic.topicArn,
      exportName: "MyTopicArn"
    },
  });
}

Accessing AWS account info​

To access the AWS account and region your app is being deployed to, use the following in your Stack instances.

stack.region;
stack.account;

The region here is the same as the one you can find in the app instance in the constructor.

Constructor​

new Stack(scope, id, props)

Parameters

Properties​

An instance of Stack has the following properties.

stage​

Type : string

The current stage of the stack.

Methods​

An instance of Stack has the following methods.

addDefaultFunctionBinding​

addDefaultFunctionBinding(bind)

Parameters

  • bind Array<SSTConstruct>

Binds additional resources to be applied to all Lambda functions in the stack.

app.addDefaultFunctionBinding([STRIPE_KEY, bucket]);

addDefaultFunctionConfig​

caution

This function signature has been deprecated.

addDefaultFunctionConfig(config)

Adds additional default config to be applied to all Lambda functions in the stack.

// Change
stack.addDefaultFunctionConfig([STRIPE_KEY]);

// To
stack.addDefaultFunctionBinding([STRIPE_KEY]);

The "addDefaultFunctionConfig" method will be removed in SST v2. Pass Parameters and Secrets in through the "addDefaultFunctionBinding" function. Read more about how to upgrade here — https://docs.serverless-stack.com/upgrade-guide#upgrade-to-v116

addDefaultFunctionEnv​

addDefaultFunctionEnv(environment)

Parameters

  • environment Record<string, string>

Adds additional default environment variables to be applied to all Lambda functions in the stack.

stack.addDefaultFunctionEnv({
  DYNAMO_TABLE: table.name
});

addDefaultFunctionLayers​

addDefaultFunctionLayers(layers)

Parameters

Adds additional default layers to be applied to all Lambda functions in the stack.

stack.addDefaultFunctionLayers(["arn:aws:lambda:us-east-1:123456789012:layer:nodejs:3"]);

addDefaultFunctionPermissions​

addDefaultFunctionPermissions(permissions)

Parameters

Adds additional default Permissions to be applied to all Lambda functions in the stack.

stack.addDefaultFunctionPermissions(["sqs", "s3"]);

addOutputs​

addOutputs(outputs)

Parameters

Add outputs to this stack

stack.addOutputs({
  TableName: table.name,
});
stack.addOutputs({
  TableName: {
    value: table.name,
    exportName: "MyTableName",
  }
});

getAllFunctions​

getAllFunctions()

Returns all the Function instances in this stack.

stack.getAllFunctions();

setDefaultFunctionProps​

setDefaultFunctionProps(props)

Parameters

The default function props to be applied to all the Lambda functions in the stack.

stack.setDefaultFunctionProps({
  srcPath: "backend",
  runtime: "nodejs16.x",
});

setStackMetadata​

setStackMetadata(metadata)

Parameters

  • metadata any